March equinox

UT date and time of
equinoxes and solstices on Earth[1][2]
event equinox solstice equinox solstice
month March[3] June[4] September[5] December[6]
year day time day time day time day time
2019 20 21:58 21 15:54 23 07:50 22 04:19
2020 20 03:50 20 21:43 22 13:31 21 10:03
2021 20 09:37 21 03:32 22 19:21 21 15:59
2022 20 15:33 21 09:14 23 01:04 21 21:48
2023 20 21:25 21 14:58 23 06:50 22 03:28
2024 20 03:07 20 20:51 22 12:44 21 09:20
2025 20 09:02 21 02:42 22 18:20 21 15:03
2026 20 14:46 21 08:25 23 00:06 21 20:50
2027 20 20:25 21 14:11 23 06:02 22 02:43
2028 20 02:17 20 20:02 22 11:45 21 08:20
2029 20 08:01 21 01:48 22 17:37 21 14:14
Illumination of Earth by the Sun on the day of an equinox

The March equinox[7][8] or northward equinox[9] is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (spring equinox) in the Northern Hemisphere and as the autumnal equinox (autumn equinox or fall equinox) in the Southern Hemisphere.[8][7][10]

On the Gregorian calendar at 0° longitude, the northward equinox can occur as early as 19 March (which happened most recently in 1796, and will happen next in 2044). And it can occur as late as 21 March (which happened most recently in 2007, and will happen next in 2102). For a common year the computed time slippage is about 5 hours 49 minutes later than the previous year, and for a leap year about 18 hours 11 minutes earlier than the previous year. Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than one day from 20 March each year.

The March equinox may be taken to mark the beginning of astronomical spring and the end of astronomical winter in the Northern Hemisphere but marks the beginning of astronomical autumn and the end of astronomical summer in the Southern Hemisphere.[11]

In astronomy, the March equinox is the zero point of sidereal time and, consequently, the right ascension and ecliptic longitude.[12] It also serves as a reference for calendars and celebrations in many cultures and religions.

  1. ^ Astronomical Applications Department of USNO. "Earth's Seasons - Equinoxes, Solstices, Perihelion, and Aphelion". Retrieved 1 August 2022.
  2. ^ "Solstices and Equinoxes: 2001 to 2100". AstroPixels.com. 20 February 2018. Retrieved 21 December 2018.
  3. ^ Équinoxe de printemps entre 1583 et 2999
  4. ^ Solstice d’été de 1583 à 2999
  5. ^ Équinoxe d’automne de 1583 à 2999
  6. ^ Solstice d’hiver
  7. ^ a b Serway, Raymond; Jewett, John (8 January 2013). Physics for Scientists and Engineers. Cengage Learning. p. 409. ISBN 978-1-285-53187-8.
  8. ^ a b United States Naval Training Command (1972). Navigation compendium. U.S. Govt. Print. Off. p. 88.
  9. ^ "Embracing the Equinox". Night Sky Network. Jet Propulsion Laboratory. 18 February 2022. Retrieved 19 July 2022.
  10. ^ Desonie, Dana (2008). Polar Regions: Human Impacts. Infobase Publishing. p. 6. ISBN 978-1-4381-0569-7.
  11. ^ "Defining Seasons". timeanddate.com.
  12. ^ Zeilik, M.; Gregory, S. A. (1998). Introductory Astronomy & Astrophysics (4th ed.). Saunders College Publishing. p. 36. ISBN 0030062284.